EL-E: An Assistive Mobile Manipulator that Autonomously Fetches Objects from Flat Surfaces.
Abstract
Assistive mobile robots that autonomously manipulate objects within
everyday settings have the potential to improve the lives of the
elderly, injured, and disabled. Within this paper, we present the most
recent version of the assistive mobile manipulator EL-E with a focus on
the subsystem that enables the robot to retrieve objects from and
deliver objects to flat surfaces. Once provided with a 3D location via
brief illumination with a laser pointer, the robot autonomously
approaches the location and then either grasps the nearest object or
places an object. We describe our mplementation in detail, while
highlighting design principles and themes, including the use of
specialized behaviors, task-relevant features, and low-dimensional
representations.
We also present evaluations of
EL-E’s performance relative to common forms of variation. We tested
EL-E’s ability to approach and grasp objects from the 25 object
categories that were ranked most important for robotic retrieval by
motor-impaired patients from the Emory ALS Center. Although reliability
varied, EL-E succeeded at least once with objects from 21 out of 25 of
these categories. EL-E also approached and grasped a cordless telephone
on 12 different surfaces including floors, tables, and counter tops
with 100% success. The same test using a vitamin pill (ca. 15mm ×5mm
×5mm) resulted in 58% success.
Paper
EL-E: An Assistive Mobile Manipulator that Autonomously Fetches Objects from Flat Surfaces.
Advait Jain and Charles C. Kemp. Autonomous Robots, 2010. (pdf, bibtex)
Code and Hardware for the Tilting Hokuyo sensor
We
mounted a Hokuyo laser range finder on to a servo which enabled the
robot, EL-E, to get 3D point clouds of the environment. We used point
clouds from this Tilting Hokuyo sensor for horizontal plane
segmentation and object segmentation. Python code, information about
the hardware setup, and a CAD model of a custom bracket to mount the
Hokuyo on to the servo can be found here:
http://www.hsi.gatech.edu/hrl-wiki/index.php/Tilting_Hokuyo